Dynamic coupling system and method of solar photovoltaic power generation and electrocatalytic carbon dioxide reduction reaction

Abstract

This invention provides a dynamic coupling system and method for solar photovoltaic power generation and electrocatalytic carbon dioxide reduction reaction. Solar energy is converted into electrical energy by a photovoltaic panel to power the electrocatalytic carbon dioxide reduction reaction. Solar radiation sensors and temperature sensors collect data on the solar irradiance and operating temperature of the photovoltaic panel surface, respectively. A coupling controller controls the connection and disconnection of the flowing electrolyzer based on the solar irradiance and operating temperature, ensuring that the flowing electrolyzer performs the electrochemical carbon dioxide reduction reaction within a preset current density range. This avoids electrode flooding and achieves stable ethylene synthesis under varying environmental conditions.

Description

Technical Field

[0001] This invention belongs to the field of solar energy utilization technology and relates to a dynamic coupling system and method for solar photovoltaic power generation and electrocatalytic carbon dioxide reduction reaction, which can achieve stable synthesis of specific hydrocarbon products under varying operating conditions. Background Technology

[0002] With the continuous development of human civilization, the demand for energy is increasing. The storage and utilization of renewable energy has become a widely concerned issue. Among known renewable energy sources, solar energy is the most widely distributed and abundant. The solar energy supplied to the Earth's surface is 9600 times the current global energy consumption; approximately 10% of the solar energy received by 0.3% of the Earth's surface area would be sufficient to meet the projected energy demand in 2050. Therefore, efficiently converting solar energy into fuel is a current solution to this problem and has long been a research hotspot in the energy sector. The technology combining solar photovoltaic power generation with electrocatalytic carbon dioxide reduction (CO2 reduction) shows promising development prospects. Electrocatalytic CO2 reduction technology can convert electrical energy and carbon dioxide into easily stored hydrocarbons, reducing CO2 emissions while providing raw materials for the chemical industry and fuel for the energy sector. Solar-driven electrocatalytic CO2 reduction offers a solution to mitigating the greenhouse effect and addressing the issues of solar energy storage and utilization.

[0003] Over the past few decades, research on solar-driven electrocatalytic carbon dioxide reduction has developed rapidly, and many systems have been established for solar-driven carbon dioxide reduction. Commonly used systems include photocatalytic (PC) systems, photovoltaic-electrochemical (PV-EC) systems, and photoelectrochemical (PEC) systems. Among these production systems, photovoltaic-coupled electrochemical and photoelectrochemical systems exhibit higher solar-to-fuel efficiency (STF). From the perspective of energy conversion efficiency alone, photovoltaic-coupled electrochemical is the most efficient among all technical routes.

[0004] Currently, research on electrochemical carbon dioxide reduction (CO2 reduction) focuses primarily on catalytic materials, with insufficient attention paid to its coupling and matching with photovoltaics. Most current photovoltaic and electrochemical systems employ indirect coupling via converter elements, which, while ensuring high photovoltaic energy conversion efficiency, suffers from coupling energy losses. The CO2 reduction reaction pathway is complex, producing a wide variety of products, and is mainly influenced by parameters such as current density and voltage during the reaction process. When environmental parameters such as irradiance and operating temperature change, the current and voltage output of photovoltaic cells fluctuate, directly affecting the current and voltage of the CO2 reduction reaction system and ultimately influencing product selectivity. This is especially true at speeds exceeding 260 mA·cm⁻¹. -2 Electrode flooding is a common phenomenon that occurs at high current densities. Electrode flooding is a term frequently used in electrochemistry. It refers to the excessive penetration or even filling of the electrode pores by the electrolyte, preventing gas from reaching the catalytically active sites of the electrode. When flooding is not present, the hydrophobic gas-diffusion layer (GDL) limits electrolyte intrusion into the gas side, ensuring CO2 flux. However, once the electrolyte wets the GDL pores, the liquid diffusion length increases to a point where the CO2 flux cannot meet the current CO2 reduction requirements, hindering the reaction. Furthermore, the entire wetted portion of the electrode will favor HER, promoting H2 generation and leading to a decrease in ethylene selectivity.

[0005] Therefore, it is necessary to explore new control strategies for the direct coupling of photovoltaic and electrochemical systems to reduce coupling losses, avoid electrode flooding, and ensure the stable synthesis of specific hydrocarbon products under varying environmental conditions. Summary of the Invention

[0006] To address the current problems of high energy loss, high current density electrode immersion, and unstable synthesis of certain products in photovoltaic electrochemical coupling, this invention provides a dynamic coupling system and method for solar photovoltaic power generation and electrocatalytic carbon dioxide reduction reaction.

[0007] This invention is achieved through the following technical solution:

[0008] This invention provides a dynamic coupling system for solar photovoltaic power generation and electrocatalytic carbon dioxide reduction reaction, including a photovoltaic panel, a coupling controller, an electrocatalytic reactor, a solar radiation sensor, and a temperature sensor;

[0009] The solar radiation sensor is used to collect the solar irradiance intensity irradiating the surface of the photovoltaic panel and transmit it to the coupling controller; the temperature sensor is used to collect the operating temperature of the photovoltaic panel surface and transmit it to the coupling controller.

[0010] The electrocatalytic reactor is equipped with an electrolytic cell group electrically connected to the photovoltaic panel. The electrolytic cell group consists of several identical flow electrolytic cells connected in parallel. The flow electrolytic cells are used for the electrocatalytic reduction of carbon dioxide to ethylene. The coupling controller calculates the number of flow electrolytic cells required to maintain the current density of the flow electrolytic cells within a preset current density range based on the received solar irradiance and operating temperature, and controls the number of flow electrolytic cells connected to the electrolytic cell group according to the required number of flow electrolytic cells.

[0011] Preferably, the flowing electrolytic cell includes, from one side to the other, an anode plate, an anode, a sealing gasket, an intermediate chamber, an ion exchange membrane, a sealing gasket, a cathode, and a cathode plate; the positive electrode of the photovoltaic panel is connected to the anode of the flowing electrolytic cell via an electromagnetic relay, and the negative electrode of the photovoltaic panel is connected to the cathode of the flowing electrolytic cell via an electromagnetic relay; the coupling controller controls the electrical connection between the photovoltaic panel and the flowing electrolytic cell via an electromagnetic relay.

[0012] Furthermore, the cathode is obtained by using a Y30T carbon paper supported electrocatalyst that has undergone hydrophobic pretreatment.

[0013] Furthermore, the anode plate has a first electrolyte solution inlet and a first drain outlet, the intermediate chamber has a second electrolyte solution inlet and a second drain outlet, and the cathode plate has a carbon dioxide gas inlet and a mixed gas outlet. The flow electrolysis cells are arranged in sequence, with the mixed gas outlet of the previous flow electrolysis cell connected to the carbon dioxide gas inlet of the next flow electrolysis cell, the first drain outlet of the previous flow electrolysis cell connected to the first electrolyte solution inlet of the next flow electrolysis cell, and the second drain outlet of the previous flow electrolysis cell connected to the second electrolyte solution inlet of the next flow electrolysis cell.

[0014] Furthermore, the portion of the cathode plate opposite to the cathode is configured as a cavity structure, and both the carbon dioxide gas inlet and the mixed gas outlet are connected to the cavity structure.

[0015] Furthermore, the portion of the anode plate opposite to the anode is a flow channel, one end of which is connected to the inlet of the first electrolyte solution, and the other end of which is connected to the first drain outlet.

[0016] Furthermore, the carbon dioxide gas inlet of the first flow electrolyzer is connected to the carbon dioxide gas tank via a hose and a carbon dioxide gas valve; the first electrolyte solution inlet and the second electrolyte solution inlet of the first flow electrolyzer are both connected to the electrolyte solution tank via a peristaltic pump; the mixed gas outlet of the last flow electrolyzer is connected to a gas chromatograph; and the first and second drain outlets of the last flow electrolyzer are both equipped with drain valves.

[0017] Preferably, the solar radiation sensor is a photoelectric solar radiation sensor, and the temperature sensor is a Pt100 adhesive temperature sensor.

[0018] This invention also provides a dynamic coupling method for solar photovoltaic power generation and electrocatalytic carbon dioxide reduction reaction, based on the aforementioned dynamic coupling system for solar photovoltaic power generation and electrocatalytic carbon dioxide reduction reaction, comprising:

[0019] A solar radiation sensor collects the solar irradiance intensity illuminating the photovoltaic panel and transmits it to a coupling controller; a temperature sensor collects the operating temperature of the photovoltaic panel and transmits it to the coupling controller; a flowing electrolytic cell electrocatalyzes the reduction of carbon dioxide to ethylene.

[0020] The coupling controller calculates the number of flowing electrolyzers required to maintain the current density of the flowing electrolyzers within a preset current density range based on the received solar irradiance and operating temperature, and controls the number of flowing electrolyzers connected to the electrolyzer group according to the required number of flowing electrolyzers.

[0021] Preferably, the coupling controller calculates the number of flowing electrolyzers required to maintain the current density of the flowing electrolyzers within a preset current density range based on the received solar irradiance and operating temperature. Specifically:

[0022] The photovoltaic model formula is as follows:

[0023]

[0024] In the formula: q is the electron charge number, C; k is the Boltzmann constant, m 2 ·kg·s -2 ·K -1 N s The number of electrolytic cells connected in series with the photovoltaic panel; A is the ideality factor of the semiconductor in the photovoltaic panel; I s This is the reverse saturation current value; V OC,STC Here is the open-circuit voltage under STC, in V; K V Voltage temperature coefficient, %·K -1 ;I SC,STC Let K be the short-circuit current under STC, A; I The photocurrent temperature coefficient is expressed as %·K. -1 V mp,STC I is the maximum power point voltage under STC. mp,STC V is the maximum power point current under STC. t Let V be the thermal voltage of the photovoltaic module, which is defined as:

[0025] The formula for the fuel cell stack model is as follows:

[0026]

[0027] Where Ns is the number of electrolytic cells connected in series with the photovoltaic panels; N p e represents the number of flow electrolyzers connected in parallel within the electrolyzer group. rev R is the reversible potential voltage, V, representing the minimum voltage required for an electrochemical reaction to occur; i Ω represents the resistive heat loss, which is expressed as the slope of the IV curve of the flow electrolyzer; j is the current density, mA·cm. -2 S represents the cathode reaction area participating in the reaction in the flowing electrolytic cell, in cm². 2 ;

[0028] Under the constraint of satisfying the preset current density range, by solving equations (1) to (10) simultaneously, the number of flow electrolytic cells that need to be connected in parallel in the electrolytic cell group can be obtained.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] This invention relates to a dynamic coupling system for solar photovoltaic power generation and electrocatalytic carbon dioxide reduction reaction. The system converts solar energy into electrical energy through photovoltaic panels to power the electrocatalytic carbon dioxide reduction reaction. Solar radiation sensors and temperature sensors collect data on the solar irradiance and operating temperature of the photovoltaic panel surface, respectively. A coupling controller controls the connection and disconnection of the flowing electrolyzer based on these parameters, ensuring the electrochemical carbon dioxide reduction reaction occurs within a preset current density range. This avoids electrode flooding and achieves stable ethylene synthesis under varying environmental conditions. Through the coupling of photovoltaic power generation and electrocatalysis, the entire system stably achieves 35-40% ethylene (C2H2) selectivity under outdoor varying conditions. The main advantage of this invention is the efficient utilization of light energy through load regulation, achieving both high selectivity and high energy conversion efficiency. By directly coupling solar energy with electrocatalysis and introducing it into carbon dioxide reduction, the system achieves stable synthesis of specific hydrocarbon products under varying conditions. Therefore, this invention solves the problems of unstable ethylene synthesis under varying environmental conditions caused by solar energy alone and high coupling energy loss, providing a solution for the industrial application of photovoltaic direct coupling electrochemical carbon dioxide reduction technology.

[0031] Furthermore, the flow electrolytic cell of the present invention uses a cavity on the cathode plate side for mass transfer on the gas side. Compared with the traditional flow channel structure, the cavity structure design can better avoid electrode drowning. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is a schematic diagram of the dynamic coupling system of solar photovoltaic power generation and electrocatalytic carbon dioxide reduction reaction involved in this invention.

[0034] Figure 2 This is a schematic diagram of the electrocatalytic reactor circuit and mass transfer route involved in the present invention.

[0035] Figure 3 The diagram shows the structure of a single flow electrolysis cell in the electrocatalytic reactor of the present invention; (a) front view; (b) left view; (c) top view; (d) cross-sectional view of the anode and anode conductive sheet; (e) cross-sectional view of the cathode and cathode conductive sheet.

[0036] Figure 4 This is the operational logic diagram of the coupled controller involved in the structural diagram of a single flow electrolysis cell in the electrocatalytic reactor of the present invention.

[0037] Figure 5 This is a functional diagram of the coupling control model involved in the present invention.

[0038] The numbers in the diagram above are: 1. Photovoltaic panel; 2. Solar radiation sensor; 3. Coupler controller; 4. Electrocatalytic reactor; 5. Negative electrode; 6. Positive electrode; 7. Carbon dioxide valve; 8. Carbon dioxide tank; 9. Peristaltic pump; 10. Electrolyte solution tank; 11. Gas chromatograph; 12. Drain valve; 13. Anode plate; 14-1. Anode conductive sheet; 14-2. Sealing gasket; 15. Intermediate chamber; 16. Ion exchange membrane; 17. Cathode; 18-1. Cathode conductive sheet; 18-2. Cathode plate; 19. Carbon dioxide gas inlet; 20. Mixed gas outlet; 21. Second electrolyte solution inlet; 22. Second drain outlet; 23. First electrolyte solution inlet; 24. First drain outlet; 25. Detailed Implementation

[0039] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0040] It should be noted that the process equipment or apparatus not specifically mentioned in the following embodiments are all conventional equipment or apparatus in the art.

[0041] It should be noted that the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to these processes, methods, products, or apparatuses. Furthermore, unless otherwise stated, the numbering of each method step is merely a convenient tool for identifying each method step, and not intended to limit the order of the method steps or define the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention.

[0042] Furthermore, it should be noted that the terms "first," "second," etc., used in this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. The terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," "outer," etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. In addition, unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly; for example, they can refer to a fixed connection or a detachable connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements.

[0043] See Figure 1 The present invention provides a dynamic coupling system for solar photovoltaic power generation and electrocatalytic carbon dioxide reduction reaction, comprising a photovoltaic panel 1, a coupling controller 3, an electrocatalytic reactor 4, a solar radiation sensor 2, and a temperature sensor.

[0044] The solar radiation sensor 2 is used to collect the solar irradiance intensity irradiated on the photovoltaic panel 1 and transmit it to the coupling controller 3; the temperature sensor is used to collect the operating temperature of the photovoltaic panel 1 and transmit it to the coupling controller 3.

[0045] The electrocatalytic reactor 4 is equipped with several identical flow electrolysis cells (GDEs), which are used for the electrocatalytic reduction of carbon dioxide to ethylene. The coupling controller 3 calculates the number of flow electrolysis cells required to maintain a preset current density based on the received solar irradiance and operating temperature, and controls the number of flow electrolysis cells connected to the photovoltaic panel 1 according to the required number of flow electrolysis cells. The electrical connection between the flow electrolysis cells connected to the photovoltaic panel 1 is in parallel.

[0046] In some specific embodiments, the solar radiation sensor 2 is a photoelectric solar radiation sensor and is disposed on the front side of the photovoltaic panel 1. The temperature sensor is preferably a Pt100 adhesive temperature sensor and is disposed on the back side of the photovoltaic panel 1.

[0047] See Figure 2 The electrocatalytic reactor 4 contains several flow electrolysis cells connected in parallel to form an electrolysis cell group. The circuits of each flow electrolysis cell are connected in parallel, while the gas-liquid transmission is connected in series using flexible hoses.

[0048] See Figure 3 The diagram shows the assembly structure of the flowing electrolytic cell. From one side to the other, the flowing electrolytic cell includes, in sequence, an anode plate 13, an anode 14-1, a sealing gasket 15, an intermediate chamber 16, an ion exchange membrane 17, a sealing gasket 15, a cathode 18-1, and a cathode plate 19. One end of the anode 14-1 is connected to an anode conductive plate 14-2, and one end of the cathode 18-1 is connected to a cathode conductive plate 18-2.

[0049] The photovoltaic panel 1 is considered as a power source, providing the electrical energy required for the electrocatalytic reaction in the electrocatalytic reactor 4. Specifically, the positive electrode 6 of the photovoltaic panel 1 is connected to the anode conductive plate 14-2 on the upper part of the electrocatalytic reactor 4 via a wire, and the negative electrode 5 of the photovoltaic panel 1 is connected to the cathode conductive plate 18-2 on the upper part of the electrocatalytic reactor 4 via a wire.

[0050] The anode plate 13 has a first electrolyte solution inlet 24 and a first drain outlet 25. The intermediate chamber 16 has a second electrolyte solution inlet 22 and a second drain outlet 23. The cathode plate 19 has a carbon dioxide gas inlet 20 and a mixed gas outlet 21. The flow electrolysis cells are arranged in sequence. The mixed gas outlet 21 of the previous flow electrolysis cell is connected to the carbon dioxide gas inlet 20 of the next flow electrolysis cell. The first drain outlet 25 of the previous flow electrolysis cell is connected to the first electrolyte solution inlet 24 of the next flow electrolysis cell. The second drain outlet 23 of the previous flow electrolysis cell is connected to the second electrolyte solution inlet 22 of the next flow electrolysis cell. The carbon dioxide gas inlet 20 of the first flow electrolyzer is connected to the carbon dioxide gas tank 8 via a hose and a carbon dioxide gas valve 7; the first electrolyte solution inlet 24 and the second electrolyte solution inlet 22 of the first flow electrolyzer are both connected to the electrolyte solution tank 10 via a peristaltic pump 9; the mixed gas outlet 21 of the last flow electrolyzer is connected to a gas chromatograph 11 to detect gaseous products; the first drain outlet 25 and the second drain outlet 23 of the last flow electrolyzer are both equipped with drain valves 12.

[0051] The portion of the cathode plate 19 opposite to the cathode 18-1 is configured as a cavity structure, and the carbon dioxide gas inlet 20 and the mixed gas outlet 21 are both connected to the cavity structure, thereby avoiding electrode drowning.

[0052] The portion of the anode plate 13 opposite to the anode 14-1 is a flow channel. One end of the flow channel is connected to the first electrolyte solution inlet 24, and the other end of the flow channel is connected to the first drain outlet 25.

[0053] The working principle of this invention is explained in detail below:

[0054] The principle of photovoltaics is the photovoltaic effect, also known as the photovoltaic effect, which utilizes the photovoltaic properties of semiconductor materials. A photovoltaic cell is structured as a semiconductor diode. When sunlight shines on the pn junction of the diode, new electron-hole pairs are formed. Under the influence of an electric field, holes flow from the n-type region to the p-type region, while electrons move in the opposite direction, thus generating a voltage. If an external circuit (such as a wire or load) is connected to the two ends of the photovoltaic cell, a current will be generated.

[0055] In terms of electrocatalysis, solar energy is converted into electrical energy by photovoltaic panels 1 containing photovoltaic cells, which drives the electrochemical reaction in the flow electrolyzer. Carbon dioxide in the flow electrolyzer is reduced at the cathode 18-1 to generate carbon-containing products. The ion exchange membrane 17 restricts the passage of specific charged ions, ensuring the normal movement of charges in the electrolyte and preventing the diffusion of cathode and anode products to the counter electrode to cause reverse reactions.

[0056] See Figure 4The coupling controller 3 connects to an electromagnetic relay, which controls the opening and closing of the electrical connection between the flowing electrolytic cell and the photovoltaic panel 1, thus connecting or disconnecting the flow electrolytic cell from the photovoltaic panel 1. The coupling controller 3 selects the current density of the flowing electrolytic cell as the control parameter. Within a preset current density range, it iteratively calculates the number of flowing electrolytic cells whose current density remains within the preset range by inputting the solar irradiance G and operating temperature T into the microcontroller. The output result controls the number of flowing electrolytic cells connected to the photovoltaic panel 1 in the electrocatalytic reactor.

[0057] From an electrical perspective, changing the number of electrolytic cells connected in series or parallel within an electrolytic cell group alters the overall impedance of the group, thus changing its volt-ampere characteristic curve. This causes the corresponding electrolytic cell's I-V operating characteristic curve to shift along the voltage or current axis, changing the operating point and consequently altering the system current and voltage. By designing the circuit with parallel connections for the electrolytic cell group, the operating point can remain stable within a certain range despite changes in external conditions.

[0058] See Figure 5 By constructing a photovoltaic model and a stack model, within the set control boundary, equations (1) to (10) are solved simultaneously, and the number of flowing electrolytic cells is obtained through iterative calculation.

[0059] The formula for building a photovoltaic model is as follows:

[0060]

[0061] Photovoltaic panels can operate under normal atmospheric conditions, but the electrical parameters on their performance parameter sheets are obtained based on Standard Test Conditions (STC). The STC temperature T... STC At 25°C, the irradiation intensity G STC 1000W·m -2 In equation (3), V OC I SC V mp and I mp All four parameters are primarily based on solar irradiance G (unit: W·m). -2 The changes in ) and operating temperature T (unit / K) can be calculated using equations (4), (5), (6) and (7), respectively:

[0062]

[0063] In the formula: q is the electronic charge number (C), which is 1.602 × 10⁻⁶. -19C; k is the Boltzmann constant, m 2 ·kg·s -2 ·K -1 N s N represents the number of electrolytic cells connected in series with photovoltaic panels in this embodiment of the invention. s Take 1; A is the ideality factor of the semiconductor in the photovoltaic panel; I s This is the reverse saturation current value; V OC,STC Here is the open-circuit voltage under STC, in V; K V Voltage temperature coefficient (%) %·K -1 ;I SC,STC Let K be the short-circuit current under STC, A; I The temperature coefficient of photocurrent (%) is given by K. -1 V mp,STC I is the maximum power point voltage under STC. mp,STC V is the maximum power point current under STC. t The thermal voltage of a photovoltaic module, in V, is defined as follows:

[0064]

[0065] V OC I SC V mp and I mp Substituting into equation (3), we calculate A. Substituting A into equation (2), we calculate the reverse saturation current value I. s Then I s Substitute into equation (1) to obtain the output current I under different voltages.

[0066] The fuel cell stack model is as follows:

[0067]

[0068] Where Ns is the number of electrolytic cells connected in series with the photovoltaic panels; N p e represents the number of flow electrolyzers connected in parallel in the electrolyzer group. rev R is the reversible potential voltage, V, representing the minimum voltage required for an electrochemical reaction to occur. i Ω represents the resistive heat loss, which is expressed as the slope of the IV curve of the flow electrolyzer; j is the current density, mA·cm.-2 S represents the cathode reaction area (cm²) of the electrolytic cell assembly. 2 .

[0069] In order to obtain R i and e rev This invention uses cyclic voltammetry to test and collect relevant data on a single flow electrolyzer and an electrolyzer group with different numbers of flow electrolyzers connected together. Using the least squares method, a polynomial curve is fitted to the IV curve of the electrolyzer group, thereby obtaining the Ri of the electrocatalytic reaction system of this invention. i and e rev Thus, the final fuel cell stack model is obtained.

[0070] The IV curve fitting formula for the electrolytic cell group of the reaction system in this embodiment of the invention is as follows:

[0071]

[0072] Within the preset current density range, by solving equations (1) to (10) simultaneously, the number of flow electrolytic cells that need to be connected in parallel in the electrolytic cell group can be obtained.

[0073] Under the constraint of satisfying the preset current density range, the simultaneous equations (1) to (10) are solved by iterative solution. The solar irradiance G and the working temperature T are obtained by solar radiation sensor and temperature sensor, respectively. Given an initial voltage V, the current can be calculated according to the photovoltaic model. Substituting the initial voltage V and current into the stack model, the number of flowing electrolytic cells is calculated, and then the current density of the electrolytic cell group can be obtained. It is determined whether the current density meets the preset current density range. If it does, the result is output. If it does not, the voltage V is updated and recalculated until the current density meets the preset current density range. The number of iterations will affect the sensitivity of the control system and the complexity of the algorithm. Therefore, in order to improve the iteration speed, the Newton method is used. The expression of this method is as follows:

[0074]

[0075] In the formula: x n f(x) is the value of the nth iteration. n f′(x) is the iterative calculation formula; n ) is f(x n The derivative of ).

[0076] The working process of this invention is described as follows:

[0077] After the system is installed, the photovoltaic panel 1 fully absorbs sunlight to generate current. The positive electrode 6 and negative electrode 5 of the photovoltaic panel 1 are connected to the anode 14-1 and cathode 18-1 of the flow electrolysis cell, respectively. The carbon dioxide gas valve 7 is opened to introduce carbon dioxide into the electrocatalytic reactor 4. At the same time, the peristaltic pump 9 and the drain valve 12 are opened to introduce electrolyte solution into the electrocatalytic reactor 4. After fully contacting the catalyst on the surface of the cathode 18-1, the photovoltaic panel 1 transfers electrons to the cathode 18-1 in the flow electrolysis cell through the negative electrode 5. The electrons react with carbon dioxide on the surface of the catalyst to generate ethylene. At the same time, the coupling controller 3 determines and controls the number of flow electrolysis cells to be connected to the system based on the solar irradiance intensity and operating temperature on the surface of the photovoltaic panel 1, so that the current density of the flow electrolysis cells is maintained within the preset current density range. The mixed gas outlet 21 of the electrocatalytic reactor 4 is connected to the gas chromatograph 11 for analysis and product collection. Real-time monitoring data is realized through microcontroller programming, and remote real-time monitoring can be realized by combining remote control software.

[0078] The electrolyte solution used in this embodiment of the invention is a 1 mol / L potassium hydroxide solution, the anode is a Pt electrode, the anode material on the anode surface is nickel-iron hydroxide synthesized by electrodeposition, and the cathode is prepared according to 1 mg·cm⁻¹. -2 The electrocatalyst loading is sprayed onto Y30T carbon paper that has undergone hydrophobic pretreatment. The electrocatalyst is potassium hydroxide doped with 40-nanometer copper nanoparticles. In this embodiment of the invention, the flowing electrolytic cell uses plexiglass material, and the sealing gasket 15 uses a polytetrafluoroethylene gasket. The photovoltaic panel 1 uses a monocrystalline silicon solar cell with a high output power of 5W. The control element in the coupling controller 3 uses an STM32F407 microcontroller, and the software used in the coupling controller 3 is Keil uVision5 from Keil Software, Inc.

[0079] A single flow electrolyzer operates at 250-260 mA·cm⁻¹ -2 At current densities or within a voltage range of 3.5-3.6V, ethylene selectivity of up to 41% can be obtained.

[0080] In this embodiment of the invention, the number of connected flow electrolysis cells is controlled using the method of the present invention based on two parameters: irradiation intensity and operating temperature, thereby controlling the current density of the entire electrocatalytic reactor 4 within a set current density range of 180-250 mA·cm⁻¹. -2 During outdoor testing, the current density was consistently controlled at 200-260 mA·cm⁻¹. -2 The outdoor irradiance during the testing process ranged from 160 to 900 W·m. -2The photovoltaic operating temperature is 30-58℃. Analysis revealed that the selectivity of the gaseous product ethylene remained essentially at 35%-40%. Experimental results showed that, with the support of the control system, by continuously adjusting the number of connected flowing electrolyzers, the entire system ultimately achieved an outdoor operating temperature of 200-260 mA·cm⁻¹. -2 At a current density of 3.3-3.6V, approximately 40% ethylene selectivity was achieved. Compared to systems without a control system, the reaction system with a control system exhibited relatively higher ethylene selectivity and also suppressed electrode drowning.

[0081] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A dynamic coupling system for solar photovoltaic power generation and electrocatalytic carbon dioxide reduction reaction, characterized in that, It includes a photovoltaic panel (1), a coupling controller (3), an electrocatalytic reactor (4), a solar radiation sensor (2), and a temperature sensor; The solar radiation sensor (2) is used to collect the solar irradiance intensity irradiated on the surface of the photovoltaic panel (1) and transmit it to the coupling controller (3). The temperature sensor is used to collect the working temperature of the surface of the photovoltaic panel (1) and transmit it to the coupling controller (3). The electrocatalytic reactor (4) is equipped with an electrolytic cell group electrically connected to the photovoltaic panel (1). The electrolytic cell group consists of several identical flowing electrolytic cells connected in parallel. The flowing electrolytic cells are used for electrocatalytic reduction of carbon dioxide to produce ethylene. The coupling controller (3) calculates the number of flowing electrolytic cells required to maintain the current density of the flowing electrolytic cells within a preset current density range based on the received solar irradiance and operating temperature. It then controls the number of flowing electrolytic cells connected to the electrolytic cell group based on the required number of flowing electrolytic cells. The method for calculating the number of flowing electrolytic cells is as follows: The photovoltaic model formula is as follows: （1） （2） （3） （4） （5） （6） （7） In the formula: q C is the electron charge number. k For Boltzmann constant, m 2 kg s -2 K -1 ; N s This refers to the number of electrolytic cells connected in series with the photovoltaic panels; A The ideal factor for semiconductors in photovoltaic panels; I s This is the reverse saturation current value; V OC,STC The open-circuit voltage under STC, in V; K V Voltage temperature coefficient, %·K -1 ; I SC,STC Let STC be the short-circuit current, in A; K I The photocurrent temperature coefficient is %·K. -1 ; V mp,STC This is the maximum power point voltage under STC. I mp,STC This is the maximum power point current under STC. V t Let V be the thermal voltage of the photovoltaic module, which is defined as: （8） The formula for the fuel cell stack model is as follows: （9） （10） in, Ns This refers to the number of electrolytic cells connected in series with the photovoltaic panels; N p This refers to the number of flow electrolyzers connected in parallel within the electrolyzer group; e rev It is a reversible potential voltage. V , which represents the minimum voltage required for an electrochemical reaction to occur; R i The resistance is the heat loss, expressed in Ω, representing the resistance of a flowing electrolytic cell. IV The slope of the curve represents the resistance heat loss term; j is the current density, mA·cm. -2 ; S The cathode reaction area participating in the reaction in the flowing electrolytic cell is in cm². 2 ; Under the constraint of satisfying the preset current density range, by solving equations (1) to (10) simultaneously, the number of flow electrolytic cells that need to be connected in parallel in the electrolytic cell group can be obtained. The flowing electrolytic cell, from one side to the other, includes an anode plate (13), an anode (14-1), a sealing gasket (15), an intermediate chamber (16), an ion exchange membrane (17), a sealing gasket (15), a cathode (18-1), and a cathode plate (19); the positive electrode (6) of the photovoltaic panel (1) is connected to the anode (14-1) of the flowing electrolytic cell via an electromagnetic relay, and the negative electrode (5) of the photovoltaic panel (1) is connected to the cathode (18-1) of the flowing electrolytic cell via an electromagnetic relay; the coupling controller (3) controls the electrical connection between the photovoltaic panel (1) and the flowing electrolytic cell via an electromagnetic relay. The anode plate (13) is provided with a first electrolyte solution inlet (24) and a first drain outlet (25), the intermediate chamber (16) is provided with a second electrolyte solution inlet (22) and a second drain outlet (23), and the cathode plate (19) is provided with a carbon dioxide gas inlet (20) and a mixed gas outlet (21). The flow electrolysis cells are arranged in sequence, with the mixed gas outlet (21) of the previous flow electrolysis cell connected to the carbon dioxide gas inlet (20) of the next flow electrolysis cell, the first drain outlet (25) of the previous flow electrolysis cell connected to the first electrolyte solution inlet (24) of the next flow electrolysis cell, and the second drain outlet (23) of the previous flow electrolysis cell connected to the second electrolyte solution inlet (22) of the next flow electrolysis cell. The portion of the cathode plate (19) opposite to the cathode (18-1) is configured as a cavity structure, and the carbon dioxide gas inlet (20) and the mixed gas outlet (21) are both connected to the cavity structure.

2. The dynamic coupling system for solar photovoltaic power generation and electrocatalytic carbon dioxide reduction reaction according to claim 1, characterized in that, The cathode (18-1) is obtained by using Y30T carbon paper supported electrocatalyst that has undergone hydrophobic pretreatment.

3. The dynamic coupling system of solar photovoltaic power generation and electrocatalytic carbon dioxide reduction reaction according to claim 1, characterized in that, The part of the anode plate (13) opposite to the anode (14-1) is a flow channel. One end of the flow channel is connected to the first electrolyte solution inlet (24), and the other end of the flow channel is connected to the first drain outlet (25).

4. The dynamic coupling system for solar photovoltaic power generation and electrocatalytic carbon dioxide reduction reaction according to claim 1, characterized in that, The carbon dioxide gas inlet (20) of the first flow electrolyzer is connected to the carbon dioxide gas tank (8) via a hose and a carbon dioxide gas valve (7); the first electrolyte solution inlet (24) and the second electrolyte solution inlet (22) of the first flow electrolyzer are both connected to the electrolyte solution tank (10) via a peristaltic pump (9); the mixed gas outlet (21) of the last flow electrolyzer is connected to a gas chromatograph (11); the first drain outlet (25) and the second drain outlet (23) of the last flow electrolyzer are both equipped with drain valves (12).

5. The dynamic coupling system for solar photovoltaic power generation and electrocatalytic carbon dioxide reduction reaction according to claim 1, characterized in that, The solar radiation sensor (2) is a photoelectric solar radiation sensor, and the temperature sensor is a Pt100 adhesive temperature sensor.

6. A method for dynamically coupling solar photovoltaic power generation with electrocatalytic carbon dioxide reduction reaction, characterized in that, The dynamic coupling system of solar photovoltaic power generation and electrocatalytic carbon dioxide reduction reaction according to any one of claims 1-5 includes: The solar radiation sensor (2) collects the solar irradiance intensity irradiated on the photovoltaic panel (1) and transmits it to the coupling controller (3); the temperature sensor collects the operating temperature of the photovoltaic panel (1) and transmits it to the coupling controller (3); the flow electrolysis cell electrocatalyzes the reduction of carbon dioxide to produce ethylene; The coupling controller (3) calculates the number of flowing electrolytic cells required to maintain the current density of the flowing electrolytic cells within the preset current density range based on the received solar irradiance and operating temperature, and controls the number of flowing electrolytic cells connected to the electrolytic cell group based on the number of flowing electrolytic cells required to be connected.

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